<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .one {
            width: 200px;
            height: 200px;
            background-color: skyblue;
            transition: all .3s;
        }

        .two {
            transform: rotate(720deg);
        }
    </style>
    <script src="jquery.min.js"></script>
</head>
<body>
    <div class="one two"></div>
    <script>
        var  one = document.querySelector('one');
        // 重新赋值   替换原来的类名
        // one.className = "two";

        // address 是追加类名
        // $('.one').address('three');

        // 删除单个类名
        $('.one').removeClass('one');
    </script>
</body>
</html>